Bad values from GetV1()

[Wile_E_Coyote]

Problem description (more than 5 years old):

TTree::Draw GetW, GetV1, GetV2, GetV3, GetV4, GetVal

In the TTree::Draw method description, I find: “The content will be the last GetSelectedRows() % GetEstimate() values calculated.” Shouldn’t it be something like: “The content will be the last min(GetSelectedRows(), GetEstimate()) values calculated.”?

Possible solutions:

The fastest way to read all tree branch data?

{ TFile *f = TFile::Open("some_file.root"); TTree *t; f->GetObject("some_tree", t); t->SetEstimate(-1); // keep all results (assumes one result per entry) Long64_t n = t->Draw("some_leaf", "", "goff"); #if 1 /* 0 or 1 */ if (n > t->GetEstimate()) // just a precaution { t->SetEstimate(n); t->Draw("some_leaf", "", "goff"); } #endif /* 0 or 1 */ for (Long64_t i = 0; i < n; i++) std::cout << t->GetV1()[i] << std::endl; }

How to push data to vector from branch tree

#include "TTree.h" #include "TGraph.h" #include "TString.h" #include "TPad.h" #include "TMath.h" #include <iostream> TGraph *DrawGraph(const char *xname, const char *yname, TTree *tree, const char *selection = "", const char *gname = "MyGraph") { TGraph *g = ((TGraph*)0); if (!(xname && xname[0] && yname && yname[0] && tree)) return g; if (!selection) selection = ""; if (!(gname && gname[0])) gname = "MyGraph"; tree->SetEstimate(-1); // keep all results (assumes one r…